The Internet is an international data network connecting personal computing devices and servers. The Internet enables people to access a wide variety of content. Images, audio, video, and web pages for many different topics are accessible via the Internet. The Internet provides an opportunity for content providers to present content to users. Content is generally served as part of a document, for example, as text, audio or visual media, or interactive elements. Documents, or the content of documents, can be presented, for example, as a web page.
Many Internet content providing methods customize content based on information related to the user who is viewing a document. For example, characteristics and/or interests of the viewing user may be used to choose content that is likely to capture the attention of the content viewer. Such systems fail to account for opportunities that may exist in the interaction of the user with other content available on the Internet.